press releases

January 2nd 2016

WHAT TO LOOK FOR WHEN BUYING DIAMOND JEWELLERY

What to look for when buying diamond jewellery

We realize that diamonds are still a woman's 'Best Friend''. Perennially classic, diamonds like Women symbolize elegance, grace and strength. Women today are constantly seeking to make style statements with their diamond jewellery.

Whether you're considering a gift of diamond jewelry for someone special, the most important aspect to look for is the quality of the diamond. Here is some information to help you get the best quality diamond jewelry for your money.

The 5 C's

The value of a diamond is determined by what is commonly referred to as the 4Cs: cut, color, clarity and carat weight. Today, there is also a "5th C" called "Certification". Each of the 5C's is important and the most valuable diamonds are those that possess the best of all these five elements.

Cut:

Among the 5C's of diamond value, the cut is considered the most critical. Cut refers to the proportions, polish and symmetry also known as the finish of the diamond. These factors determine the fire and brilliance of a diamond. Well-cut diamonds sell at a premium and poorly cut diamonds sell at lower prices.

Since the quality of the cut is directly responsible for the stone's beauty, the precision with which the facets are arranged is of prime importance.  They determine the amount of light reflected to the eye, called brilliance. Good cut diamonds are equally well proportioned, but their reflective powers are less than their more highly graded relations. At the low end of reflectivity, fair and poor diamonds may reflect no more than 40% of the entering light.

Carat:

Carat is the unit of weight for the diamond.  A carat is further subdivided in 100 points (0.01 carat = l point). One carat is equal to 0.20 grams.  Value per carat increases with carat size, because larger rough diamonds occur less frequently.  In other words, 2 half-carat diamonds taken together will not cost as much as 1 one-carat diamond, as the one-carat stone is rarer

Clarity:

Clarity describes the clearness or purity of a diamond. This is determined by the number, size, nature, and location of the internal (inclusions) and external (blemishes) imperfections.

In keeping with the precise nature of determining diamond value, clarity has its own scale of measurement. The clarity scale accounts for these microscopic imperfections. Gems with the fewest inclusions are the rarest and costliest.

Colour:

Rarely does the absence of something add value. Not so for diamonds, where the absence of color is nearly always the mark of value. Diamonds purest in brilliance have no colors. Most diamonds vary from colourless to yellow. To determine this all diamonds need to be compared with an internationally accepted master set of stones, the colour of which ranges from D or colourless to Z, the yellowest. Colors can also range from intense yellow to brown, blue, green, pink and red. These fancy colors are rare and therefore more valuable.

Certification:

Based on the 4C's, a diamond certificate identifies and attests to the specific characteristics of your diamond. A diamond, which is certified, will provide you with the confidence and assurance whilst making a buying decision.

A diamond is certified by an independent laboratory by certified gemologists and assures that your diamond is what it claims to be.

As you begin to appreciate the different qualities of diamonds, you will decide what is important to you. Some women prefer size and sparkle to a finer quality while others want perfection and will sacrifice size. The important thing is that you get the value for what you want. So, go ahead and indulge your loved one this Valentines Day with a diamond.

January 2nd 2016

ARTICLE ON SPINEL - A GEMSTONE

ARTICLE ON SPINEL - A GEMSTONE

As part of IDL education program to the trade about gemstones and jewelry, here is a new article on one of the most beautiful gemstones available in the market.

The stone described is the Spinel.

Spinel is the magnesium aluminum member of the larger Spinel group of minerals.

It has the formula MgAl2O4.

It crystallize in the cubic (isometric) crystal system, with the oxide anions arranged in a cubic close-packed lattice and the cations (Mg and Al) occupying some or all of the octahedral and tetrahedral sites in the lattice.

It has an imperfect octahedral cleavage and a conchoidal fracture.

Its hardness is 8, its specific gravity is 3.5-4.1 (depending on the variety) and it is transparent to opaque with a vitreous to dull luster.

It can be virtually any color of the spectrum with various shades of red, blue, green, yellow, brown or black.

Spinel has long been found in the gemstone-bearing gravel of Sri Lanka. More recently the Badakshan Province (Afghanistan) and Mogok in Burma have supplied some of the best samples of spinels.

Other sources of gem quality spinels are also in the marbles of Luc Yen (Vietnam), Mahenge and Matombo (Tanzania), Tsavo (Kenya) and in the gravels of Tunduru (Tanzania) and Ilakaka (Madagascar).

Spinel is found as a metamorphic mineral, and also as a primary mineral in rare mafic igneous rocks.

These igneous rocks are relatively deficient in alkalis relative to aluminium so aluminium oxide may form as the mineral corundum or may combine with magnesia to form spinel. This is why spinel and ruby are often found together.

 Some spinels are among the most famous gemstones:

 Tipical shape of the crystals of spinel is the octahedron:

 

 

 Samples of faceted spinels showing part of the vast variety of colors available in nature:

  

 hot pink spinel from Mahenge Tanzania

 

 lavender violet spinel from Sri Lanka

 

purplish red spinel from Cambodia.

 

Early in the 20th century synthetic spinel was produced by the "flame fusion" process known as Vernuill method.

For many years it was used as an imitation found in birthstone jewelry and high school class rings.

Only recently, as the level of gemological awareness of consumers has grown, then spinel finally is getting some respect as the rare and beautiful gem it is.

This increased appreciation derives not only from the gem's inherent rarity and beauty, but also from the fact that virtually all spinels in today's market are unenhanced.

As more extensive and invasive treatments are given to lower grade rubies and sapphires to improve their color or clarity, spinel's natural beauty, and still relatively modest prices, become ever more inviting.

 

Francesco Natale
Chief Gemologist - IDL Dubai

January 1st 2016

YELLOW DIAMONDS: A RESEARCH CASE AT IDL

Yellow diamonds: a research case at IDL

By Francesco Natale (Chief Gemologist - IDL Dubai)

Few days ago we received a jewelry set from a client. It was composed of a necklace, a ring and one pair of earrings. It was 18k white gold containing "colorless" diamonds and "Fancy intense" yellow to orangy-yellow diamonds.

 The "white" stones where identified as natural diamonds with natural color.

The fancy color ones raised some questions as soon as we started the visual observation of the color and internal characteristics.

What was immediately suspicious was the absolute uniformity of the color of all the stones (approx 90), showing identical tones and saturations.

After microscopic observations it was clear that further research was needed to clear the origin of the stones.

In such cases advanced testing is required to prove the origin, natural or synthetic, of the stone and the origin of the color, natural or treated.

We asked the owner of the jewels to unmount few yellow diamonds to be able to perform all the necessary measurements and analysis that would be impossible to do in mounted conditions.

 What was visible with magnification were some suspicious internal characteristics such as:

  • Pinpoints "dispersed-like" clouds
  • Single and multiple crystals with "metallic" luster
  • The pattern of the yellow-colorless color zoning

It was becoming clear that the next step of the research had to focus on the "natural vs synthetic" determination of these stones.

The FTIR (Infrared spectroscopy) confirmed that all the samples were type Ib diamonds. It means that they contain single N (nitrogen) atoms as impurity in the structure of the diamond, providing the typical yellow color of these stones.

This is important information since all the synthetic yellow diamonds, created with the "HPHT" method, are type Ib.

A further analysis on the UV-Vis-NIR spectrometer showed again typical spectra for this type of diamonds.

Only one of the stones had relevant peaks referable to the presence of the metallic element "nickel" inside the stone. The laboratory process to create synthetic diamonds involves the use of some "solvents" containing metallic elements such as "nickel".

Natural diamonds don't contain this element so this was again an important information regarding the origin of these stones. Probably the most decisive instrument that can prove the natural-synthetic origin of a diamond is the Diamond View (from DTC).

It's an instrument working on the basis of the "fluorescence pattern" of the stone when exposed to very low wavelength UV light.The way the crystal grows, deep inside the earth or in a laboratory, results in different arrangement of the internal structure. This is visible, even in faceted stones, as different patterns of the growth sectors reacting (or not) with different colors to the UV radiation.

In our specimens we observed clear evidence of a "cubo-octahedral" structure of the crystal that is typical of synthetic diamonds.

So after a series of standard gemological observations and advanced research analysis we were able to confirm the Synthetic origin of the diamonds we received from the client.

We only tested 4 stones (taken as representative samples) out of approx 90 mounted in the jewelry set but we can confidently consider that all of them are of the same synthetic origin.